Process for breaking petroleum emulsions employing certain oxyalkylated n-methylglucamines



May 26; 1959 M. DE GROOTE ET AL 2,888,404 PROCESS FOR BREAKING PETROLEUM EMULSIONS EMPLOYING CERTAIN OXYALKYLATED N-METHYLGLUCAMINES Filed Aug. 10, 1954 .v BINARY REACTION PRODUCT FOR OXYETHYLATION A A WA METHYLGLUCAMINE United States Patent 20 Claims. (Cl. 252-344) This invention relates to processes or procedures particularly adapted for preventing, breaking or resolving emulsions of the water-in-oil type, and particularly petroleum emulsions.

Our invention provides an economical and rapid process for resolving petroleum emulsions of the water-in-oil type that are commonly referred to as cutoil, roily oil, emulsified oil, etc., and which comprise fine droplets of naturally-occurring waters or brines dispersed in a more or less permanent state throughout the oil which constitutes the continuous phase of the emulsion.

It also provides an economical and rapid process for I separating emulsions which have been prepared under controlled conditions from mineral oil, such as crude oil and relatively soft waters or weak brines. Controlled emulsification and subsequent demulsification under the conditions just mentioned are of significant value in removing impurities particularly inorganic salts, from pipelineoil.

More specifically then, the present invention is concerned with a process for breaking petroleum emulsions employing a demulsifier including a cogeneric mixture of a homologous series of glycol ethers of N-methylglucamine. The cogeneric mixture is derived exclusively from N-methylglucamine, propylene oxide and ethylene oxide in such weight proportions so the average composition of said cogeneric mixture stated in terms of initial reactants lies approximately within the trapezoid of the accompanying drawing in which the minimum N-methylglucamine content is at least 1.75% and which trapezoid is identified by the fact that its area lies within the straight lines connecting A, B, F, E. Our preference by far is to use the compositions which represent less than one-half of this total area, to Wit, the smaller trapezoid A, B, D, C. Reference to methylglucamine means N-methylglucamine in all instances.

It isimmaterial as to whether one reacts the amine with propylene oxide first and then with ethylene oxide, or with I ethylene oxide and then with propylene oxide; or, for that matter, one may employ a mixture of the two oxides; or, if desired, one may add a small amount of ethylene oxide, then propylene oxide, and then more ethylene oxide.

Referring to the hereto attached drawing it is simplified by noting that one may react methylglucamine with enough ethylene oxide so the binary reaction product falls Within the mixture identified by the line CO-DD on the ice the area of the trapezoid and preferably within the area of the small trapezoid A, B, D, C.

For the purpose of resolving petroleum emulsions of the water-in-oil type, we prefer to employ oxyalkylated derivatives, which are obtained by the use of monoepoxides, in such manner that the derivatives so obtained have sufiicient hydrophile character to meet at least the test set forth in U.S. Patent No. 2,499,368, dated March 7, 1950, to De 'Groote and Keiser. In said patent such test for emuls'ification using a water-insoluble solvent, generally xylene, is described as an index of surface activity.

The above mentioned test, i.e., a conventional emulsification test, simply means that the preferred product for demulsification is soluble in a solvent having hydrophobe properties or in an oxygenated water insoluble or even a fraction of a water-soluble hydrocarbon solvent and that when shaken with water the product may remain in the nonaqueous solvent or, for that matter, it may pass into the aqueous solvent. In other words, although it is xylene soluble, for example, it may also be Water soluble to an equal or greater degree.

For purpose of convenience, what is said hereinafter will -be-divided into three parts:

Part 1 is concerned with the oxyalkylation of N- methylglucamine in a general way;

' Part 2 is concerned with the oxyalkylation of N- methylglucamine using two different oxides, i.e., propylene oxide and ethylene oxide so as to produce derivatives falling within said compositional limits as previously described and noted hereinafter in detail;

Part 3 is concerned with the resolution of petroleum emulsions of the water-in-oil type by means of thepreviously described chemical compounds.

PART 1 The oxyalkylation of amines is well known. This applies particularly to reactions involving monoepoxides having not over 4 carbon atoms such as ethylene oxide and propylene oxide. As to the oxyalkylation of a monoamine such as cyclohexylamine, see U.S. Patent 7 No. 2,626,922, dated January 27, 1953, to De Groote.

As totheoxyalkylation of a polyamine, see U.S. Patents Nos. 2,552,530,- dated May 15, 1951, to De Groote.

The oxyalkylation of an amine is comparable to other well known oxyalkylations and under certain conditions may require variation. There is no problem if the amine is a liquid or if it is xylene-soluble or soluble in an equivalent solvent, or can be melted and reacted at the melting point. In the case of methylglucamine the product is a solid and one of the mostsatisfactory procedures is to use a slurry of the finely powdered materia1. .in'xy1ene comparable to the oxyalkylation of sorbitol, As to this procedure, see Example A in U.S. Patent No. 2,552,528, dated May 15, 1951, to De Groote. Sincemethylglucamine melts at l28129 C. it is obvious that although one starts with a solid that the extremity of the graph which shows combinations derived solely from methylglucamine and ethylene oxide. After obtaining such binary reaction product it can then be reacted with propylene oxide so as to bring it within the area of the trapezoid A, B, F, E, or preferably within the I smaller trapezoid A, B, D, C.

Similarly, one can produce a binary reaction product from methylglucamine and propylene oxide as identified by'the comparable line AABB and subjectthis reaction product to oxyethylation so as to bring the composition I product is a' liquid at the reaction temperatures employed in the majority of instances.

In order to illustrate why the herein contemplated compounds or said products are cogeneric mixtures and not single chemical compounds, and why they must be described in terms of manufacture, and molal ratio or percentage ratio of reactants, reference is made to a monohydric alcohol. Methylglucamine is a polyhydric alcohol having 5 reactive hydrogen atoms attached to oxygen and also one attached to nitrogen. Thus, for the present purpose it might be considered the same as an amino alcohol having 6 hydroxyl radicals. However, for the moment, one can forget the hydrogen atom attached to nitrogen and even the pluralityfof hydroxyl radicals and simply consider what happens when a monohydric alcohol is subjected to oxyalkylation.

If one selects any hydroxylated compound and subjectssuch compound to oxyalkylation, such as oxyethylation or oxypropylation, it becomes obvious that one is really producing a polymer of the alkylene oxide except for the terminal group. This is particularly true where the amount of oxide added is comparatively large, for instance, 10, 20, 30, 40, or 50 units. If such a compound is subjected to oxyethy'lation so as to introduce 30 units of ethylene oxide, it is well known that one does not obtain a single constituent which, for sake of convenience, may be indicated as Instead, one obtains a cogeneric mixture of closely related homologous compounds in which the formula may l 4 be a liquid at the reaction temperature which usually is above the melting point.

Specific reference is made to the instant application which is concerned with ethylene oxide, and propylene oxide, or the equivalents. Actually, whether one uses ethylene oxide or, for that matter, propylene oxide, one preferably starts with either the powdered solid sus-- pended as a slurry in xylene or a similar inactive solvent; or one employs an alkylene carbonate such as ethylene carbonate or propylene carbonate, for the initial oxyalkylation. When such initial oxyalkylation has gone far enough to convert the solid mass into a r product which is at least liquid at oxyalkylation tembe shown as the following: RO(C H O),,H, wherein 1.

n, as far as the statistical average goes, is 30, but the individual members present in significant amount may vary from instances where n has a value of 25 and perhaps less, to a point where n may represent 35 or more. Such mixture is, as stated, a cogen'eric closely related series of touching homologous compounds. Considerable investigation has been made in regard to the distribution curves for linear polymers. Attention is directed to the article entitled Fundamental Principles of Condensation Polymerization, by Paul J. Flory, which appeared in Chemical Reviews, volume 39, No. 1, page 137.

Unfortunately, as has been pointed out by Flory and other investigators, there is no satisfactory method,

perature it can be subjected to the oxides as difierentiated from the carbonates. The carbonates, of course, cost more than the oxides.

In any event, any one of a number of well known procedures may be employed and referencehas been made to U.S. Patent No. 2,652,394, dated September 15, 1953, to De Groote. This particular patent happensto be concerned with sucrose but, as a matter of fact, one can just as readily substitute methylglucamine and the r reaction will go just as rapidly and, in fact, perhaps more based on either experimental or mathemetica'l examination, of indicating the exact proportion of the various members of touching homologous series which appear in cogeneric condensation products of the kind de-" scribed. This means that firom the practical standpoint, i.e., the ability to describe how to make the product under consideration and how to repeat such production time after time without difliculty, it is necessary to resort to some other method of description.

What has been said in regard to a monohydric com pound of course is multiplied many times in the case r.

of a polyhydric compound such as methylglucamine.

Although acid catalysts are used in oxyalkylations they are used to a lesser extent in the oxyalkylations of basic amines and the like. Under such circumstances one may have to use enough of the acidic catalyst to neutralize the basicity of the product and convert into a salt. This is not true where certain clays or prepared earths are used which act as acidic catalysts. In any event, it is our preference to use basic catalysts such as caustic soda, sodium methylate. or the like.

PART 2 The oxyalkylation of an amine, particularly a pri-- mary amine or secondary amine or a hydroxylated amine regardless of whether it is primary, secondary, or tertiary, is comparatively simple and has been dew scribed repeatedly in the literature. It the product is a liquid such as triethanolamine one can proceed to treat with an alkylene oxide such as ethylene oxide, propylene oxide, or butylene oxide, at least in the early stages if desired without adding any catalyst. Generally speaking, if oxyalkylation is rather extensive as in the present instance, one requires a catalyst after the initial stage and it is just as simple to add it from the very beginning. If the amine is a solid at ordinary temperature and this is true in regard to methylglucamine, one can readily follow the procedure of using a slurry in the same manner that is employed in connection other solids although not necessarily nitrogen-contain ing. Reference is made to products such as sorbitol, sucrose, glucose, .pentaerythritol, dipentaerythritol, etc.

previously pointed out methylglucamine is apt to H clave (capacity 15 liters).

rapidly than with sucrose. Referring to said aforemen tioned patent, the same procedure using propylene oxide, or ethylene oxide, can be employed simply using mixed oxides instead.

It is not believed any examples are necessary to illustrate such well known procedure but for purposes of illustration the following are included:

Example 1a The reaction vessel employed was a stainless steel autoclave with the usual devices for heating, heat control, stirrer, inlet, outlet, etc., which is conventional in this type of apparatus. The capacity was approximately 4 liters. The stirrer operated at a speed of approximately 250 r.p.m. There were charged into the autoclave 500 grams of methylglycamine, 300 grams of xylene, and 15 grams of sodium methylate. The autoclave was sealed, swept with nitrogen gas and stirring started immediately and heat applied. The temperature was allowed to rise to approximately 152 C. At this particular time the addition of propylene oxide was started.- Propylene oxide was added continuously at such speed that it was absorbed by the reaction as added. The amount added in this operation was 1500 grams. The time required to add the propylene oxide was two hours. During this period the temperature was maintained at to C., using cooling water through the inner coils when necessary and otherwise applying heat it required. The maximum pressure during the reaction was 50 pounds per square inch. Ignoring the xylene and sodium methylate and considering only the methylglucamine for convenience, the resultant product represents 3 parts by weight of propylene oxide to one part by weight of methylglucamine. The xylene present represented approximately .6 of one part by weight.

Example 2a The reaction mass was transferred to a larger auto- Without adding any more solvent or any more xylene the procedure was repeated so as to add another 1500 grams of propylene oxide under substantially the same operating conditions but requiring about 3 hours for the addition. At the end of this step the ratio represented approximately 6 to 1 (ratio propylene oxide to methylglucamine).

Example 3a In a third step, instead of adding 1500 grams of propylene oxide, 1625 grams were added. The reaction slowed up and required approximately 6 hours, using the sarne operatingtemperatures and pressures. The

tatio at the end'ofthe third step was 9.25 parts by weight of propylene-oxide per weight of methylglucamine.

' I, Example 411 i At'theend ofthis step the autoclave was opened and additional grams of sodium methylate added, the autoclave" flushed out as before, and the fourth and ,oxyalkyla'tion' completed, using- 1625 grams of propyl'ene oxide, and the oxyalkylation was complete within 3 /4 hours using the same temperature range and pressure as previously. At the end ofthe reaction the prod- 'u'ct represented approximately 12.5 parts of propylene oxi e; by weight: to one part of methylglucamine.

l ,'Having obtained oxypropylated methylglucamine the products were subjected to oxyethylation in amanner comparable to the oxyethylation of triethanolamine, or for'that matter, in the same way that oxypropylated sucrose is subjected to oxyethyla'tion in the manner described in U.S. Patent No. 2,652,394, dated September 15, 1953, to; De Groote; Indeed, the procedure is comparatively simple for the reason that one is working with a liquid also that ethylene oxide is more reactive than propylene oxide. As a result, using the same amount of catalyst one can oxyethylate more rapidly than usually at a lower pressure.

The same procedure using a slurry of methylglucamine in xylene was coupled in connection with ethylene oxide and the same mixture on a percentage basis was obtained as in the above examples where propylene oxide andmethylglucamine were used. Note what has been said-previously as to the melting point of methylglucamine.

, Iiithe' preceding procedures one oxide has been added anclthen the other. One need not follow this procedure. The two oxides can be mixed together in suitable proportions and subsequently subjected to joint oxyalkylation so as toobtain products coming within the specified limits. In such instances, of course, the oxyalkylation may be described as random oxyalkylation insofar that one cannot determine the exact location of the propylene oxide or ethylene oxide groups. In such instances the procedure again is identically the same as previously described and, as a matter of fact, we have used such methods in connection with methyl'glucamine.

\ Actually, methylglucamine at times may contain a trace of moisture. Our preference is to prepare the slurry with an'excess of xylene and distill 01f a part of the xylene so as toremove any trace of water and then flush out the mass with nitrogen. Even so, there may be a few tenths of a percent'of moisture remain although at times examination indicates-at the most it is merely a trace.

,As previously pointed out the simplest procedure of allis to prepare a binary reaction product of ethylene oxide on the one handor methylglucamine and propylene oxide on the other hand, and reactwith the other oxide. Note line CCDD which indicates that in the binary reaction product obtained from methylglucamine and ethylene oxide one employs approximately 66.6% to 96.5% of ethylene oxide and approximately 3.5% to 33.4% of methylglucamine.

Similarly, if one refers to the line AA-BB it means one would employ from 1.95% of methylglucamine up to 14.3% of methylglucamine and from 85.7% of propylene oxide up to 98.05% of propylene oxide.

Actually, in other operations we have proceeded to do as follows: Mixed the methylglucamine with an aromatic petroleum solvent and with powdered caustic soda. We have stirred this mixture at 125 to 130 C. for a short period of time, approximately one-half hour, flushed out with nitrogen, and then subjected to vacuum so as to eliminate any moisture. We then started to oxypropylate and 'contin'ued until oxypropylation was complete and then immediately followed withethylene oxide. In these examples the amount of materials used are indicated in pounds, and in each instance, of course, a suitable size TABLE I Ethylene oxide lbs.

Caustic soda lbs.

Propyl- Time Temp; hrs. 0.

Referring again to the ratio of the initial reactants based on the trapezoid in attached drawing it will be noted that we have calculated the percentage of the three initial reactants for the points A, B, C, D, E, and F, and Nos. 1 through 14, inclusive. We have also calculated initial binary mixtures corresponding in essence to the lines CC -DD' and AA- -BB, all of which appears in selfexplanatory form in Table II, immediately following.

TABLE II Tertiary mixture percent' basis Binary intermediate mixtures percent basis Points on boundary 01 area Ethylene oxide Propyl- Methylene glueamine As previously pointed out, the oxyalkylation of methylglucamine or similar hydroxylated polyamines has been described in the literature and is described also in detail above. All one need do is employ such conventional oxyalkylation procedure to obtain products corresponding to the compositions as defined. Attention is again directed to the fact that one need not add the entire amount of either oxide at onetime but that a small portion of one could be added and then another small portion of the other, and the process repeated.

For purpose of illustration we have prepared examples in three diifere'nt ways corresponding to the compositions on the drawing. In the first seriespropylene oxide and ethylene oxide were mixed; this series is indicated asAa, Ba, etc., through and including 14a; in the second series propyleneoxide was used first followed by ethylene oxide and this series is 'in'clicat'ed as Ab, Bc', etc., through and including 1415; and finally in a third series, ethylene oxide was used firstfollowed by propylene oxide and this series is indicatedas Ac, Bc, etc., through and including 140.

TABLE III- Cornposition Composition Composition where oxides where where Composition corresponding are mixed propylene ethylene oxide to following point prior to oxide used first oxyalkylaused first followed by tion followed by propylene ethylene oxide oxide The products obtained by the above procedure usually show some color varying from a light amber to apale straw. They can be bleached in the usual fashion using bleaching clays, charcoal, or an organic bleach, such as peroxide or peracetic acid, or the like. i

There are certain variants which can be employed without detracting from the metes and bounds of the invention, but for all practical purposes there is nothing to be gained by such variants and the result is merely increased cost. For instance, any one of the two oxides can be replaced to a minor percentage and usually to a Very small degree, by oxide which would introduce substantially the same group along with a side chain, for instance, one could employ glycidyl methyl ether, glycidyl ethyl ether, glycidyl isopropyl ether, glycidyl butyl ether or the like.

Increased branching also may be eifected by the use of an amine instead of a glycide, or a methyl glycide. Thus one can use ethylene imine, or propylene imine in the same way described for glycide or methyl glycide. An additional elfect is obtained due to the basicity of'the nitrogen atom. The same thing is true as far as the inclusion of nitrogen atoms if one uses a compound of the kind previously described such as a dialkylaminoepoxy-f propane. Excellent products are obtained by reacting methylglucamine with one to 6 moles of ethylene imine and then proceeding in the same manner herein described. In the hereto appended claims reference has been made to glycol ethers of methylglucamine. Actually it well may be that the products should be referred to as polyol ethers of methylglucamine in order to emphasize the fact that the final products of reaction have more than two hydroxyl radicals. However the products may be considered as hypothetically derived by reaction of methylglucamine with the glycols, such as ethylene glycol, butylene glycol, propylene glycol, or polyglycols. For this reason there seems to be a preference to use the terminology glycol ethers of methylglucamine. I

In atrapezoid such as A, B, D, C, the area can be divided conveniently into five portions by first drawing two lines from the shorter of the two parallel sides perpendicular so as to intersect the other longer parallel line in two places, thus dividing the trapezoid into two triangles and a rectangle. The rectangle then obviously can be divided into three portions of the same size by drawing two additional lines, all of which is shown in the drawing on a larger scale andiin dotted lines only. In the hereto attached claims the-.area, within the upper apex of the trapezoidrefers to the area within such upper triangle the.

8 area within the lower apex of the trapezoid refers to such lower triangle. The area in the center of the trapezoid refers to the area defined by the, middle rectangle. The area .of one rectangle is defined by being between the .upper apex and the center rectangle, and the other by being between the lower apex and the center rectangle, all of which is perfectly plain by reference to the drawing. An attempt to draw additional lines and to number them the same trapezoid A, B, D, C, would only tend towards confusion and thus the present means is being employed to point out the various areas which, in turn, appear in the sub-generic claims hereto appended. Thus in the drawing, the area designatedV corresponds to the area within the upper triangle, the area W corresponds to the area within the lower triangle, the area X corresponds to that of the middle rectangle, and the areas Y and Z cor respond to those of the other rectangles.

PART 3 As to the use of conventional demulsifying agents, reference is made to US. Patent No. 2,626,929, dated Ian uary 7, 1953, to De Groote, and particularly to Part 3. Everything that appears therein applies with equal force and elfect to the instant process, noting only that where reference is made to Example 13b in said text beginning in column 15 and ending in column 18, reference should be to Example 5b herein described.

Having thus described our invention What we claim as new and desire to obtain by Letters Patent is: v

1. A process for, breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to a demulsifying agent including a cogeneric mixtureof a homologous series of glycol ethers of N-methylglucamine; said cogeneric mixture being derived exclusively from N-methylglucamine, propylene oxide and ethylene oxide is such weight proportion so the average compositions of said cogeneric mixture stated in terms of initial reactants. lies approximately within the trapezoid of theaccompanying drawing in which the minimum N- methylglucamine content is at least 1.75% and which trapezoid is identified bythe fact that its area lies within the straight lines A, B, F, E.

2. A process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to ;a demulsifying agent including a cogeneric mixture of a homologous series of glycol ethers of N-methylglucamine; said cogeneric mixture being derived exclusively from N-methylglucamine, propylene oxide and ethylene oxide in such weight proportion so the average compositions of said cogeneric mixture stated in terms of initial reactants lies approximately within the trapezoid of the accompanying drawing in which the minimum N- methylglucamine content is at least 1.75% and which trapezoid is identified by the fact that its area lieswithin the straight lines A, B, D, C. t

3. The process of claim 2 with the proviso that oxyal'kylation takes place in presence of an alkaline catalyst.

4. The process of claim 2 with the proviso that oxyalkylation takes place in presence of an alkaline catalyst and that at least part of the propylene oxide is added first. K

5. The process of claim 2 with the proviso that oxyalkylation takes place in presence of an alkaline catalyst and that all the propylene oxide is added first.

6. The process of claim 5 with the proviso that the reactant composition approximates a point in the area corresponding with V within the upper apex of the trapezoid A, B, D, C.

7. The process of claim 5 with the proviso thatthe reactant composition approximates a point in the area. corresponding with W within the lower apex of the trapezoid A, B, D, C.

8. The process of claim 5 'with the proviso that the reactant composition approximates a point in the area corresponding with X of the central part of the trapezoid A, B, D, C.

9. The process of claim with the proviso that the reactant composition approximates a point in the area corresponding with Y between the central part of the trapezoid A, B, D, C, and the upper apex.

10. The process of claim 5 with the proviso that the reactant composition approximates a point in the area corresponding with Z between the central part of the trapezoid A, B, D, C, and the lower apex.

11. A process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to a demulsifying agent including a cogeneric mixture of a homologous series of glycol ethers of N-methylglucamine; said cogeneric mixture being derived exclusively from N-methylglucamine, propylene oxide and ethylene oxide in such weight proportion so the average compositions of said cogeneric mixture stated in terms of initial reactants lies approximately within the trapezoid of the accompanying drawing in which the minimum N-methylglucamine content is at least 1.75% and which trapezoid is identified by the fact that its area lies within the straight lines A, B, F, E; with the proviso that the hydrophile properties of said cogeneric mixture in an equal weight of xylene are sufficient to produce an emulsion when said xylene solution is shaken vigorously with one to three volumes of water.

12. A process for breaking petroleum emulsions of the Water-in-oil type characterized by subjecting the emulsion to a demulsif ying agent including a cogeneric mixture of a homologous series of glycol ethers of N-methylglucamine; said cogeneric mixture being derived exclusively with N-methylglucamine, propylene oxide and ethylene oxide in such weight proportion so the average compositions of said cogeneric mixture stated in terms of initial reactants lies approximately within the trapezoid of the accompanying drawing in which the minimum N-methylglucamine content is at least 1.75% and which trapezoid is identified by the fact that its area lies within the straight lines A, B, D, C; with the proviso that the hydrophile properties of said cogeneric mixture in an equal weight of xylene are sufiicient to produce an emulsion when said xylene solution is shaken vigorously with one to three volumes of water.

13. The process of claim 12 with the proviso that oxyalkylation takes place in presence of an alkaline catalyst.

14. The process of claim 12 with the proviso that oxyalkylation takes place in presence of an alkaline catalyst and that at least part of the propylene oxide is added first.

15. The process of claim 12 with the proviso that oxyalkylation takes place in presence of an alkaline catalyst and that all the propylene oxide is added first.

16. The process of claim 15 with the proviso that the reactant composition approximates a point in the area corresponding with V within the upper apex of the trap ezoid A, B, D, C.

17. The process of claim 15 with the proviso that the reactant composition approximates a point in the area corresponding with W within the lower apex of the trapezoid A, B, D, C.

18. The process of claim 15 with the proviso that the reactant composition approximates a point in the area corresponding with X of the central part of the trapezoid A, B, D, C.

19. The process of claim 15 with the proviso that the reactant composition approximates a point in the area corresponding with Y between the central part of the trapezoid A, B, D, C, and the upper apex.

20. The process of claim 15 with the proviso that the reactant composition approximates a point in the area corresponding with Z between the central part of the trapezoid A, B, D, C, and the lower apex.

References Cited in the file of this patent UNITED STATES PATENTS 2,233,383 De Groote et a1. Feb. 25, 1941 2,262,736 De Groote et a1 Nov. 11, 1941 2,290,416 De Groote July 21, 1942 2,457,634 Bond et a1. Dec. 28, 1948 2,552,530 De Groote May 15, 1951 2,574,544 De Groote Nov. 31, 1951 2,589,200 Monson Mar. 11, 1952 2,622,099 Ferrero et a1. Dec. 16, 1952 2,649,483 Huscher et a1. Aug. 18, 1953 2,677,700 Jackson et a1. May 4, 1954 

1. A PROCESS FOR BREAKING PETROLEUM EMULSLIONS OF THE WATER-IN-OIL TYPE CHARACTERIZED BY SUBJECTING THE EMULSION TO A DEMULSIFYING AGENT INCLUDING A COGENERIC MIXTURE OF A HOMOLOGOUS SERIES OF GLYCOL ETHERS OF N-METHYLGLUCAMINE; SAID COGENERIC MIXTURE BEING DERIVED EXCLUSIVELY FROM N-METHYLGLUCAMINE, PROPYLENE OXIDE AND ETHYLENE OXIDE IS SUCH WEIGHT PROPORTION SO THE AVERAGE COMPOSITIONS OF SAID COGENERIC MIXTURE STATED IN TERMS OF INITIAL REACTANTS LIES APPROXIMATELY WITHIN THE TRAPEZOID OF THE ACCOMPANYING DRAWING IN WHICH THE MINIMUM NMETHYLGLUCASMINE CONTENT IS AT LEAST 1.75% AND WHICH TRAPEZOID IS IDENTIFIED BY THE FACT THAT ITS AREAS LIES WITHIN THE STRAIGHT LINES A,B,F,E. 